화학공학소재연구정보센터
Clean Technology, Vol.16, No.2, 132-139, June, 2010
Cu-Mn 혼합산화물 상에서 일산화탄소의 저온산화반응
Low Temperature CO Oxidation over Cu-Mn Mixed Oxides
E-mail:
초록
서로 다른 몰비의 Cu-Mn 혼합산화물을 공침법으로 제조하여 30℃에서 CO 산화반응을 수행하였다. 제조된 촉매는 CO 산화반응에서 반응 활성과 연관시키기 위하여 XRD, N2 흡착 및 탈착, XPS, H2-TPR 등의 특성분석을 수행하였다. 제조된 촉매의 질소흡착 등온곡선은 4형태로 7-20 nm크기의 세공이 존재하며, Mn의 함량이 증가함에 따라 BET 표면적은 17에서 205 m2·g^(-1)으로 증가하였다. XPS 분석으로 Cu-Mn 혼합산화물 상의 Cu는 주성분이 2+의 산화상태임을 확인하였고, Mn은 +3과 +4의 산화 상태를 나타냈다. Cu-Mn 촉매의 함량 및 비율에 따른 최적 활성을 실험 조사한 결과, 30℃의 반응온도에서 Cu/(Cu+Mn)의 몰비가 0.5일 때 가장 좋은 활성을 나타냈으며, 이를 기준으로 화산형 형태의 반응 곡선을 나타냈다. 수분 존재하의 CO 산화반응은 활성점에 수분과 CO의 경쟁흡착으로 촉매의 활성을 감소시켰으며 최종적으로는 활성금속 성분과 하이드록실 그룹을 형성하였기 때문이다.
The Cu-Mn mixed oxide catalysts with different molar ratios of Cu/(Cu+Mn) prepared by co-precipitation method have been investigated in CO oxidation at 30℃. The catalysts used in this study were characterized by X-ray Diffraction (XRD), N2 sorption, X-ray photoelectron spectroscopy (XPS), and H2-temperature programmed reduction (H2-TPR) to correlate with catalytic activities in CO oxidation. The N2 adsorption-desorption isotherms of Cu-Mn mixed oxide catalysts showed a type 4 having pore range of 7-20 nm and BET surface area was increased from 17 to 205 m2·g^(-1) with increasing of Mn content. The XPS analysis showed the surface oxidation state of Cu and Mn represented Cu^(2+) and the mixture of Mn^(3+) and Mn^(4+), respectively. Among the catalysts studied here, Cu/(Cu+Mn) = 0.5 catalyst showed the highest activity at 30℃ in CO oxidation and the catalytic activity showed a typical volcano-shape curve with respect to Cu/(Cu+Mn) molar ratios. The water vapor showed a prohibiting effect on the efficiency of the catalyst which is due to the competitive adsorption of carbon monoxide on the active sites of catalyst surface and finally the formation of hydroxyl group with active metals.
  1. Xu J, Mullins DR, Overbury SH, J. Catal., 243(1), 158 (2006)
  2. Wang F, Lu GX, J. Power Sources, 181(1), 120 (2008)
  3. Xu GW, Zhang ZG, J. Power Sources, 157(1), 64 (2006)
  4. van Giezen JC, van den Berg FR, Kleinen JL, van Dillen AJ, Geus JW, Catal. Today, 47(1-4), 287 (1999)
  5. Wang F, Lu G, Inter. J. Hydrogen. Energ., in press. (2010)
  6. Haruta M, Yamada N, Kobayashi T, lijima S, J. Catal., 115(2), 301 (1989)
  7. Hasegawa YI, Maki RU, Sano M, Miyake T, Appl. Catal. A: Gen., 371(1-2), 67 (2009)
  8. Morales MR, Barbero RP, Cactus LE, Fuel., 87(7), 1177 (2008)
  9. Mai H, Mengfei L, Ping F, J.Rare Earths., 24(2), 188 (2006)
  10. Craciun R, Nentwick B, Hadjiivanov K, Knozinger H, Appl. Catal. A: Gen., 243(1), 67 (2003)
  11. Wang XY, Kang Q, Li D, Appl. Catal. B: Environ., 86(3-4), 166 (2009)
  12. Tang XF, Li YG, Huang XM, Xu YD, Zhu HQ, Wang JG, Shen WJ, Appl. Catal. B: Environ., 62(3-4), 265 (2006)
  13. Hutchings GJ, Mirzaei AA, Joyner RW, Siddiqui MRH, Taylor SH, Appl. Catal. A: Gen., 166(1), 143 (1998)
  14. Lee HY, Manivannan V, Goodenough JB, J. Solid State Chem., 144(1), 220 (1999)
  15. Lee HY, Manivannan V, Goodenough JB, "Electrochemical Capacitors with KCI Electrolyte," C. R.Acad Sci. Paris, t. 2, SCrie II c, p. 565-577 (1999)
  16. Hasegawa Y, Fukumoto K, Ishima T, Yamamoto H, Sano M, Miyake T, Appl. Catal. B: Environ., 89(3-4), 420 (2009)
  17. PalDey S, Gedevanishvili S, Zhang W, Rasouli F, Appl. Catal. B: Environ., 56(3), 241 (2005)
  18. Xu R, Wang X, Wang DS, Zhou KB, Li YD, J. Catal., 237(2), 426 (2006)
  19. Morales MR, Barbero BP, Cadus LE, Appl. Catal. B: Environ., 67(3-4), 229 (2006)
  20. Reddy AS, Gopinath CS, Chilukuri S, J. Catal., 243(2), 278 (2006)
  21. Tanaka Y, Utaka T, Kikuchi R, Takeguchi T, Sasaki K, Eguchi K, J. Catal., 215(2), 271 (2003)
  22. Kramer M, Schmidt T, Stowe K, Maier WF, Appl. Catal. A: Gen., 302(2), 257 (2006)
  23. Fortunato G, Oswald II. R, Reller A, J Mater. Chem., 11(3), 905 (2001)
  24. Hamoudi S, Larachi F, Adnot A, Sayari A, J. Catal., 185(2), 333 (1999)
  25. Zhu J, Gao Q, Miropor. Mesopor. Mater., 124(1-3), 144 (2009)
  26. Papavasiliou J, Avgouropoulos G, Ioannides T, J. Catal., 251(1), 7 (2007)
  27. Wang LC, Liu Q, Huang XS, Liu YM, Cao Y, Fan KN, Appl. Catal. B: Environ., 88(1-2), 204 (2009)
  28. Zhu P, Li J, ZuO S, Zhou R, Appl. Sur. Sci., 255(5), 2903 (2009)
  29. Chen YZ, Liaw BJ, Huang CW, Appl. Catal. A: Gen., 302(2), 168 (2006)
  30. Lee HC, Kim DH, Catal. Today, 132(1-4), 109 (2008)
  31. Wu Z, Zhu H, Qin Z, Wang H, Ding J, Huang L, Wang J, Fuel., "CO Preferential Oxidation in H2-rich Stream over a CuO/CeO2 Catalyst with High H20 and C02 tolerance," in press (2010)
  32. Avgouropoulos G, Ioannides T, Appl. Catal. A: Gen., 244(1), 155 (2003)
  33. Park JW, Jeong JH, Yoon WL, Rhee YW, J. Power Sources, 132(1-2), 18 (2004)